Doctors used to counsel women against exercising during pregnancy. But while the physicians’ intentions were laudable—safety first!—it turns out there wasn’t much science to back up the medical advice. Every pregnancy is unique, of course, and it’s true that fitness may increase some pregnancy-related health risks. (Consult your doctor.) But new research suggests that many pregnant women can exercise through their second trimester and even beyond without detrimental effects.
Potential problems typically include: miscarriage, emergency caesarean sections, and perineal tears during labor. So researchers involved in two recently published studies were particularly interested in links between prenatal exercise and these medical complications. Fortunately, they found none.
A study published in the October 2018 issue of the British Journal of Sports Medicine looked at data from 46 previous studies,
comparing medical data from women who exercised during pregnancy with those who did not. While the evidence of associations was of “very low’ quality,” investigators found nothing to suggest that prenatal exercise increased the odds of miscarriage or perinatal mortality: “In plain terms, this suggests that, generally speaking, exercise is ‘safe’ with respect to miscarriage and perinatal mortality,” they concluded.
Another study, by Icelandic researchers and published in a month earlier in the same journal, focused on 130 elite female
athletes engaged in both low- and high-impact activities—comparing them with a control group. Again, “no significant differences” were found between the groups in regard to caesareans or the length of the labor. Interestingly, data suggested that elite athletes involved in low-impact activities were more likely to suffer perineal tears than elite athletes doing high-impact activities, but no statistically significant differences showed up when compared to the control group. In the end, researchers said elite female athletes had no reason to assume that their training would adversely affect their pregnancy.
In fact, many doctors now encourage their patients to work out during pregnancy. Exercise can reduce risk for excessive weight gain, gestational diabetes, and preeclampsia. But don’t overdo it. The general recommendation for pregnant women is 30 minutes of exercise a day—or 150 minutes per week. And make sure to watch your temperature and drink lots of fluids to reduce your risk of overheating and dehydration. In the end, those doctors of yore were right about one thing: Safety first.